Verification Narrative: Development of a Web-based Multi ...

baldknobdasypygalSoftware and s/w Development

Jul 4, 2012 (5 years and 2 months ago)

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Greenhouse Structures and Glazing Materials




Can synthesize information related to glazing material science with a specific
crop, market, and budget and confidently decide what type of greenhouse
covering to use for a specific application.











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Verif ication Narrative:


Development of a Web
-
based Multi
-
media Resource for
Environmental Control Modeling and Greenhouse
Education
ABSTRACT
A publicly accessible multimedia instrument for greenhouse
education was developed for global use. The instrument consists
of (1) greenhouse videos produced on site in Arizona, Vermont,
Ohio, and Florida that emphasize state
-
specific production,
environmental control, labor, and marketing issues; (2) an
interactive Flash
-
based greenhouse environment simulator that
allows users to model greenhouse environments based on climate
data from each of the four video locations; (3) a searchable digital
repository containing hundreds of useful greenhouse images,
videos, and lectures, and (4) a web
-
based method for instructors to
evaluate perceived student learning of greenhouse concepts. The
Interactive Greenhouse Environment Simulator is driven by a
mathematical model developed by engineers which is linked to a
Flash
-
based graphical user interface (GUI). Following user
selection of climate, structure, and environmental control choices,
dynamic environmental information is graphed during the
simulation, allowing users to model changes in the greenhouse
environment.
INTRODUCTION

There are over 15,500 acres of greenhouses being used to
produce annual bedding plants, herbaceous perennials, potted
flowers, cut flowers, greens, food crops, and nursery crops in the
United States (NASS, 2000).

A survey conducted by Tignor et al. (2005), identified over 84
greenhouse
-
related courses and 60 greenhouse instructors in the
U.S.

instructors of these courses rarely share educational resources,
partly because multi
-
state greenhouse industries are significantly
diverse in terms of climate, systems, and crops.

The development of educational modules that share common
conceptual issues of controlled plant environments (energy
conservation, environmental safety, labor efficiency, plant response
manipulation) is now feasible through improved computer
technology.

The objectives of our project were to (1) produce greenhouse
videos in Arizona, Vermont, Ohio, and Florida that emphasize
state
-
specific production, environmental control, labor, and
marketing issues; (2) develop an interactive Flash
-
based
greenhouse environment simulator that allows users to model
greenhouse environments based on climate data from each of the
four video locations; (3) implement a searchable digital repository
containing hundreds of useful greenhouse images, videos, and
lectures, and (4) develop a web
-
based method for instructors to
evaluate perceived student learning of greenhouse concepts.
M.E. Tignor
Department of Plant and Soil Science
The University of Vermont
Burlington, VT USA
G.A.Giacomelli, C. Kubota, and E. Fitz
Controlled Environment Agriculture Center
The University of Arizona
Tucson, AZ USA
S.B. Wilson
Department of Environmental Horticulture
The University of Florida
Fort Pierce, FL USA
T.A. Irani and E. Rhoades
Department of Agricultural Education and Communication
The University of Florida
Gainesville, FL USA
M.J. McMahon
Department of Horticulture and Crop Science
The Ohio State University
Columbus, OH USA
GREENHOUSE DVD

A video producer was contracted and sent to Vermont, Arizona,
Ohio and Florida for filming. All videos were recorded using a
digital Sony PD
-
150 with
similar subject content, shooting style,
and interview length.

Two to three hours of original video at each location were edited
and organized by topic into 55 smaller one to eight minute
segments including: introduction to the state industry, introduction
to a specific business, greenhouse structure, sample crop cycle,
crop nutrition, pest control practices, and computer use. These
clips were created to be "stand
-
alone" and can be viewed on their
own or compared and contrasted with each other.

Using a menu template, the video clips were placed on a streaming
server, archived into a digital repository, and saved onto DVDs for
distribution (Fig. 1).
GREENHOUSE ENVIRONMENT SIMULATOR
(‘A day in the life of a plant’)

An Interactive Greenhouse Environment Simulator was developed
by integrating mathematical models and an animation interface
(Flash MX Pro 2004, Macromedia, Inc., San Francisco).

The greenhouse mathematical model, based on energy balance of
the greenhouse component systems, is a set of differential
equations that are solved numerically using the Runge
-
Kutta
-
4
algorithm and implemented in Actionscript 2.0.

The model incorporates user selected information from its
database of greenhouse design, operation, and geographic climate
conditions; and graphically displays dynamic greenhouse
environmental information, including moist air properties. The
animation allows learners to model changes in the greenhouse
plant environment based on climate, structure, and environmental
control choices (Fig. 2).

Each design is created by the user, and then an internal
environmental response is simulated for a selected geographic
climate condition. Each simulation demonstrates the response of a
greenhouse system design for a 28
-
hour period to the actual hourly
climate conditions, selected from the database of four locations
with different climates. The database climate conditions include
Arizona (hot, arid, high light), Florida (hot, humid, subtropical, high
light), Vermont (cold, temperate, low light), and Ohio (cold,
temperate, humid, low light).

Designs can be completed both with and without plants in the
greenhouse, to demonstrate the cooling and humidifying effect of
plant transpiration on the greenhouse climate for any selected
design and geographic climate.

The inputs to the greenhouse simulator are discrete multiple
options, which combine to provide for the comparison of more than
32,000 possible design scenarios. Option selections include:
geographic location (Arizona, Ohio, Florida or Vermont), season
(winter, spring, summer or fall), structure type (a
-
frame, arch,
Quonset), glazing (glass, polyethylene, polycarbonate, single layer,
double layer), ventilation (absent, natural, or forced; in half and full
capacity for each option), cooling (absent and wet pads at half or
full capacity), heating (absent, half capacity, or full capacity), plant
biomass (absent, small, or large), and set points for air
temperature (no control, or temperature set points (day: 24
°
C, night: 18
°
C).
INSTRUMENT FOR ASSESSING STUDENT LEARNING

Learning assessment tools were developed and utilized in a
Greenhouse Operations and Management Course in spring 2005
(University of Vermont) and in an Introduction to Hydroponics
Course in the fall of 2005 (University of Arizona).

Students were asked to assess their initial level of competency via
a seven point scale that ranged from 1 = novice to 7 = expert, then
to supply a written verification narrative in the text box provided in
order to explain why they chose to rate themselves at a particular
level (Fig. 3).

For the post test, students completed the same assessment, and
answered the open ended question, “where did your growth
occur?”

Results indicated significant knowledge growth from pre to post
test in all competency areas (Table 2).

These results provide support for the value and effectiveness of
using multimedia instruments to teach greenhouse concepts in a
virtual environment that can be readily accessed by students no
matter where they may be.
DIGITAL REPOSITORY, LIVING GLOSSARY,
AND CENTRAL WEBSITE

DSpace is a free open source platform for constructing repositories
of digital materials (http://www.uvm.edu/wge/dsintro.htm).

Our DSpace site currently has 493 high resolution greenhouse
images (many with abstracts), 6 greenhouse design software
packages of international and domestic origin (with tutorials), 8
lectures, and 65 videos. All of the materials have been granted
educational distribution licenses by the authors or submitters and
are available for anyone to use.

In addition, an entire greenhouse glossary that consists of several
hundred definitions from the Greenhouse Operation and
Management textbook (Nelson, 2003) has been uploaded to a wiki
(http://greenhouse.pbwiki.com).

Since its inception last summer, the DSpace greenhouse digital
repository has been searched hundreds of times and thousands of
bitstream views have resulted. Forty
-
five of the digital accessions
have been viewed over 50 times, several over 80 times and one
item has been accessed 130 times.

To direct visitors to the various educational tools described above, a
central website (http://www.uvm.edu/wge/education.htm) was
developed using Macromedia Dreamweaver MX 2004 v. 7.0.1.

Statistics showing access „hits‟ to the project website are shown in
Table 1. Since inception, the site has averaged 580 unique visits
and 2,650 hits per month, thus illustrating the value of this web
-
based educational resource.
Table 1. Statistics for project website collected weekly using
AccessWatch 2.1 and summarized by month. (August 2005

January 2006).
Month
Unique visits
Total hits
August
362
2993
September
574
3141
October
697
3276
November
799
3684
December
462
1778
January
586
2644
Fig. 2. Screen capture of the greenhouse simulator illustrating
environment, structure, glazing, ventilation, cooling and heating
simulation capabilities.
Fig. 1. Greenhouse DVD consisting of edited video from four
production sites including Arizona, Florida, Ohio and Vermont.
Competency
Pre
-
test
mean
Post
-
test
mean
t
Sig.
Greenhouse structure and glazing materials
1
.
55
4
.
36
4
.
113
.
002
Greenhouse environmental impact on plant
growth and development
2
.
08
4
.
05
4
.
699
.
001
Integrated pest management
1
.
82
4
.
09
3
.
760
.
004
BMP/environmental impact of greenhouse
production
1
.
82
4
.
73
3
.
675
.
004
Plant life cycle
2
.
64
5
.
09
3
.
480
.
006
Root substrates
2
.
27
5
.
18
5
.
022
.
001
Plant nutrition
2
.
00
4
.
75
5
.
564
.
000
Irrigation
1
.
91
4
.
82
5
.
488
.
000
Packing and post harvest operation
1
.
82
3
.
82
2
.
909
.
016
Regional/national/international industry
differences
1
.
18
3
.
45
3
.
760
.
004
Table 2. Competency of knowledge growth based on pre and post
-
test means.
Fig. 3. Example of greenhouse structures and glazing materials core
competency self
-
assessment.